The present invention relates generally to the formation of integrated circuit interconnect structures, and more specifically to a technique for forming silver metal interconnects within integrated circuit devices. The present invention also relates, more generally, to the formation of a variety of semiconductor device structure such as, for example, transistors, capacitors, and interconnects.
Silver is considered an important material for manufacturing a variety of types of PCRAMS, such as dynamic random access memories (DRAMs), static random access memories (SRAMs), etc., and other integrated circuit devices. Unfortunately, there are a number of manufacturing obstacles attributable to the use of silver in integrated circuit device fabrication. Specifically, silver and silver-based materials adhere poorly to many materials utilized in integrated circuit devices. For example, a silver conductive plug adheres poorly to tungsten and it is not uncommon for a chemical mechanical planarization (CMP) process employed in integrated circuit device fabrication to result in inadvertent removal of a silver plug adhered to or contacting a tungsten layer. Accordingly, there is a continuing need for an improved silver CMP process in integrated circuit device fabrication.
This need is met by the present invention wherein a scheme for silver CMP in integrated circuit device fabrication is presented. According to one embodiment of the present invention, an integrated circuit device processing scheme is provided where an integrated circuit device is chemically and mechanically planarized with a processing slurry selected to be relatively minimally selective of silicon nitride and relatively highly selective of silver-based conductive material. According to another embodiment of the present invention, the processing slurry comprises an abrasive and an oxidizer. Methods for fabricating an integrated circuit device and processing schemes for semiconductor wafers are also provided.